The Pierburg Secondary Air Injection Pump - 721852240 is a component used in automotive engines to help reduce harmful emissions. It works by injecting fresh air into the exhaust system, which helps to burn any remaining fuel before it leaves the vehicle. This process helps to lower the levels of pollutants in the exhaust, making the vehicle more environmentally friendly. The pump is designed to be durable and efficient, providing reliable performance for an extended period of time. It is a crucial part of the emissions control system and is essential for passing emissions tests.